IO has since been nerfed but in the 7.06 patch, Team Liquid support player GH took full advantage of this little ball of love. Many times, you'll see teams ban the hard carry for their opponents. Or sometimes ban a player that may rat and split push them to death? But teams playing Team Liquid are often banning his favorite and most effective heroes: IO, Keeper of the Light, and Earthshaker. This frees hero picks for the Team Liquid carries. Quite a nice little advantage!
Here are some highlights to illustrate why teams should ban IO when playing against GH. Guy is a monster on this hero...